The present invention concerns a carbon containing heat-resistant iron-chromium-nickel base alloy composition which, in the cast state, exhibits excellent creep and rupture strengths at temperatures in the range of about 1800.degree. to 2200.degree. F, excellent creep ductility and oxidation resistance, is weldable, and can be economically manufactured under normal commercial foundry conditions.
The alloy composition of the instant invention is readily melted and can be cast either statically or centrifugally. In addition, the concerned alloy does not require heat treatment in order to obtain its exceptionally good creep and rupture properties. The alloy composition of the invention exhibits exceptional creep ductility for a high-strength cast heat-resistant alloy, with creep ductility at rupture always exceeding 15 percent in 2 inches in long-time creep rupture tests at 1800.degree. to 2200.degree. F.
Heat-resistant iron-chromium-nickel containing alloys are well known in the art and today find a myriad of uses in industry. For example, such alloys are used in high-temperature furnaces and in various types of processing equipment, such as conveyor rolls for steel processing, furnace tube hangers and supports, and reaction tubes in chemical processing. In use, these components are exposed to the combustion products of fossil fuels and, in the case of tubular products for chemical processing, to various reducing and oxidizing feed stocks. These alloys, consequently, must resist oxidation, sulfidation, and carburization. Of particular importance, however, are the creep and rupture properties of these alloys at temperatures in the range of 1800.degree. to 2200.degree. F.
While conventional alloys are generally suitable for use in connection with the foregoing purposes, they all generally suffer from a lack of good creep and rupture properties at temperatures in excess of about 1800.degree. F.
Accordingly, it is the primary objective of the present invention to provide an alloy composition which overcomes the problems associated with prior art alloys.
Other objects of the invention will be apparent to those skilled in the art from a reading of the present specification and claims.